“Webb had an existing contract with Fox Searchlight to helm
another film following 2009′s “500 (Days) of Summer.” After “The
Amazing Spider-Man” in 2012, Webb’s negotiations briefly stalled
with Sony as he was caught in a tug-of-war with Fox. Eventually,
Fox agreed to allow Webb to direct Sony’s “Spider-Man” sequel,
but only if Sony would promote its “X-Men” film for free.”

Yes, Sony agreed to run a promo for "Days of Future Past" after
"Spider-Man."

The only problem is that viewers may be confused into believing
there’s an X-Men / Spider-Man crossover in the works.